Whether the sun is going down, or just hasn't come up yet, the Sundown 250 1/2 Zip rises to the occasion. A familiar waffle-knit structure, which has always been a go-to for offering superior warmth, in the lightest and most packable package. A staple component of A/SYS-2, the Sundown is super-charged with Nuyarn merino Technology, so you won't care if the sun ever comes up. Superior Bluesign® 250GSM Nuyarn merino offers extra loft for an unmatched warmth-to-weight ratio 5x faster drying Remarkable long-term durability Superfine 18 micron non-mulesed Australian merino wool for maximum softness and wearability